We are continuing our efforts to clone the novel macrophage receptor form cDNA libraries obtained from human monocytes and from rat spleen. We have found, using quantitative autoradiography with selective iodinated ligands, that the novel macrophage receptor is expressed in the rat brain only after brain lesions resulting in cell death, such as chemical lesions of the inferior olive. The receptor expression is proportional to the degree of brain injury and to the number of injured neurons in this model. These observations indicate that determination of the expression of the novel macrophage receptor may be used as a quantitative method to estimate the degree of brain damage and neuronal death. - human macrophages/cloning/immunology/brain injury